Photochem

Natural Product Synthesis (NPS) is a cornerstone of organic chemistry, historically rooted in the dual goals of structure elucidation and synthetic strategy development for bioactive compounds. Initially focused on identifying the structures of medicinally relevant natural products, NPS has evolved into a dynamic field with applications in drug discovery, immunotherapy, and smart materials. This evolution has been propelled by advances in reaction design, mechanistic insight, and the integration of green chemistry principles. A particularly promising development in NPS is the use of photochemistry, which harnesses light—a renewable energy source—to drive chemical transformations. Photochemical reactions offer unique excited-state reactivity, enabling synthetic pathways that are often inaccessible through thermal methods. Their precision and sustainability make them ideal for modern synthetic challenges. This review explores a wide range of photochemical reactions, from classical to contemporary, emphasizing their role in total synthesis. By showcasing their potential, the review aims to encourage broader adoption of photochemical strategies in the synthesis of complex natural products, promoting innovation at the intersection of molecular complexity, sustainability, and synthetic efficiency.

Long persistent phosphors are widely used in many fields, such as LED, bioimaging, urgent lighting, temperature sensors, etc. Although green and blue long persistent phosphors are well developed, efficient orange-yellow long persistent phosphors are still relatively rare. In this work, a novel orange-yellow long-persistent phosphors Ca₂LuScGa₂Ge₂O₁₂:xPr³⁺ (CLSGGO:xPr³⁺, x = 0.003, 0.005, 0.01, 0.02, 0.03, 0.04, 0.05) are prepared and systematically investigated through its crystal structural information, photoluminescence, and persistent luminescence properties. Under ultraviolet light excitation, these phosphors exhibit orange-yellow emission stemming from the ³P₀ and ¹D₂ multiple electron transitions in the 4f level of Pr³⁺ ion. In addition, the material exhibits bright persistent luminescence. The complex garnet matrix structure of Ca₂LuScGa₂Ge₂O₁₂ provides excellent conditions for the formation of traps. Through the testing of thermoluminescence curve and function fitting, the density and depth of traps are studied; also, the storage and release process of carriers in the material are calculated in detail. A reasonable persistent luminescence mechanism is proposed for CLSGGO:0.01Pr³⁺. This work enriches the research content of photoluminescence and long persistent luminescence of Pr³⁺-doped garnet-based phosphors and paves the way for the future research of long persistent luminescent materials doped with rare earth ions.

In this study, the fluorescence (FL) behavior of a fluorenone derivative (FDMFA) in four chlorinated hydrocarbon solvents was investigated. While all four solvents have low polarities, their proticities are considerably different. Therefore, the FL properties of FDMFA could be considered to depend solely on the solvent’s proticity, with any polarity effects being insignificant. The hydrogen bond donor acidity was used as a measure of proticity, with higher values representing greater FL quenching due to vibronic coupling. The hydrogen bonding between FDMFA and the solvents could be thermodynamically controlled; thus, the FL emission was substantially enhanced during the heating process and quenched again during the cooling process. This change occurred reversibly and repeatedly. Because chlorinated hydrocarbon solvents are widely used for reaction and cleaning purposes in industrial applications, the findings of this study will be helpful in ensuring that such solvents are appropriately handled.